Correction to question, coolant temperature
 

I did't state my ? correctly and will try again. the needle is pointing to the very top of the 80C. Is this normal and how high can the pointer go before it means trouble? Thanks

Not knowing what model car!

Most MB's run between 80C & 100C and aren't overheating until 115C. NEWER cars seem to run right around the 100C mark as most of them have a higher temp thermostat.

Higher temps help with "MOST" emissions. NOT NOx